Staircases or a set of steps are used to walk from one elevation to another elevation. While steps have been around for so long that no one can say for sure about the first set of steps, one can only imagine that the first set of steps were probable stones stacked upon one another. As time went on, ways to attach the stones more permanently to one another were developed. Even before the invention of modern cement, evidence exists that ancient civilizations used certain materials to “mortar” stones together to form a set of steps. Even before blades were used to cut trees into lumber, logs were shaped into flat steps and attached to make a staircase. Not long after iron and steel were developed, they too were soon used to fabricate a set of steps.
Whatever the method used by the ancient civilizations, the method of constructing a staircase was always the same. They would gather the raw materials they were going to use and take them to the site where they were going to use them then they would fabricate the staircase using one piece at a time. This method is the most commonly used method still to this day. It usually involves bringing boards, cutting them and nailing them together or using masonry blocks, or stone, or bricks and mortaring them together. Another commonly used method today involves forming a staircase out of wood or like material and pouring concrete to take the shape of a staircase.
While a set of steps fabricated in these ways can be very beautiful and elaborate, they can also be very expensive. To make a set of steps in stone or brick is beyond the know-how of the typical home-owner and a professional mason has to be hired. Also because steps done in this fashion are stone or bricks cemented together into one large piece, these types set of steps has to be placed on a footing. If a footing were not used, any settling or shifting would cause this one large piece to crack.
To custom build a set of steps one piece at a time is not the only way to build a set of steps however, “prefabricated” steps are known in the art. “Prefabricated” staircases are built in a factory or some other location and then taken to a site where they are typically attached to the upper and lower elevations. Interior wooden staircases are the most common of these and are widely used today. Exterior staircases made of pressure treated lumber are also used. Prefabricated steel steps are commonly used for fire escapes and the like. U.S. Pat. No. 4,438,608, U.S. Pat. No. 4,802,320, and U.S. Pat. No. 4,899,504 are types of these. While prefabricated interior staircase can be very decorative and elaborate, most types of these materials can't stand up to the elements when used in the exterior.
One type of prefabricated steps that can stand up to the elements is a prefabricated concrete unit. The problem with this is that they are make of solid concrete and have to be set in place by a mechanical lift of some sort. Making it impractical for installation in some locations.
One way to solve the problems that large and heavy prefabricated units present is by developing pre-made parts specifically designed for use as a stair or staircase. Most people can assemble stair parts like these without costly professional help. While precut parts used to make a set of steps can be purchased at any local home building materials store, most are out of lumber or metal not out of masonry that can be long lasting when used in the exterior.
There are methods using some sort of block that is stacked one upon another, known in the art. Some have means of interlocking and can even be assembled without “mortaring” the blocks together. In U.S. Pat. No. 6,295,772, U.S. Pat. No. 6,176,049 and U.S. Pat. No. 5,479,746 are examples of types of masonry block that are used almost exclusively for making steps.
Recently steps have been make using split faced masonry block, U.S. Pat. No. 4,802,320 and U.S. Pat. No. 5,017,049 are examples of these blocks and can be glued together with a masonry adhesive to form a set of steps. This method allows the staircase to “give”, thereby preventing cracking. The appearance of this type of staircase is limited because of the way these blocks are manufactured. Also, any method used to build a set of steps out of blocks stacked one upon another requires the use of many blocks, not only on the outside and front face but also the totality of the inside from the ground up to the top and from side to side.
It has been known for some time in the art to build masonry steps for outdoor use using materials other than stacked blocks. U.S. Pat. No. 5,014,475, U.S. Pat. No. 4,959,935, U.S. Pat. No. 4,406,347, U.S. Pat. No. 4,250,672, and U.S. Pat. No. 4,244,154 all have masonry pieces that don't require the total area under the step treads to be built up. All these methods use a stringer type design for the risers. The trouble with a stringer design is a different sized stringer would be used for staircases with different numbers of steps. This would present a problem to supply stores that would have to carry inventories for one step units, different stringers for two step units, and so on.
U.S. Pat. No. 1,879,996, U.S. Pat. No. 2,697,931, U.S. Pat. No. 2,722,823, U.S. Pat. No. 3,025,639, U.S. Pat. No. 3,706,170 all have solid side pieces not stringers, that serve as risers. While these staircase systems also don't require the total area under the step tread to be built up, they have the same problem in that supply houses would have to carry different side pieces for each set of differing numbers of steps. These large inventories are very costly and inconvenient.
U.S. Pat. No. 2,374,905 has masonry pieces stacked upon one another not solid side pieces. But this system talks of poured concrete key-ways, thereby presenting the same problem of cracking that any solid masonry staircase would present.
It would therefore be a significant advance of the art to provide a staircase or set of steps made out of long lasting masonry pieces which could take on the appearance of natural stone or brick. And which could be easily assembled using just nuts and bolts, without having to pour footings or “cement” these pieces together. It would also be an advance in the art if these masonry pieces could be easy to handle and assembled in such a way as to use as few pieces as possible in the construction of the staircase. It would be a further advance in the art to develop a system to produce exterior staircases that could be used to build steps of differing numbers of steps and steps of differing widths using interchangeable parts. And at the same time being able to inventory only small amounts of system pieces to do this.